Electromagnetic sound reproducer



Oct. 11 1927 F. DIETRICH ET AL ELECTROMAGNETIC SOUND REPRODUCER Filed March 5, 1926 I .L E;' l

I AZ arzze y/ iatented Oct. 11, 1927.

UNITED STATES ATENT. OFFICE FREDERICK DIETBICH, OI NEW YORK, N. Y., AND H/GERNS, OF EAST ORANGE, NEW .TEESEY, LSSIGNOBS TO BBANDES LABORATORIES, ARK, NEW JERSEY. A CORPORATIONOF NEW (JERSEY.

mo, 01' NEW- MAGNETIC sounnmsnaonncan.

Application filed 1mm 5, incit -m No. 92,540.

Our invention relates broadly to electro ma etic sound reproducers, and more particu arly to a construction of cone speaker for use in radio broadcast reproduction.

One of't he ob'ects ,of our invention is to provide a simplified construction of cone speaker which may be manufactured inexpensivelyion a quantity production basis and yet have parts arranged for the efiicient reproduction of a broad band of frequencies over the entire musical scale.

Another object of our invention is to provide a. construction of cone. speaker having its parts arranged for the reinforcement of sound waves emanating from the front of a (one diaphragm by the sound waves emanating from the rear'of the cone diaphragm for reproduction of radio broadcast entertainmentat relatively large amplitude.

Still anothcr object of our invt-ntion is to provide an assembly of conical sound reproducing diaphragm in a casing shaped in such manner,that sound emanating from the rear of the diaphragm is reflected in such manner as to reinforce the sound emahating from the front of the iaphragm for efficiently reproducing sound over a broad band of frequencies? 1 y Still another object of our invention is to provide a casing for an electromagnetic sound reproducer hzfvin its parts pressed from sheet metal and icked together to form a rigid casing from the interior of which sound is directed outwardly in a direction by which the sound may be distributed over a relatively large area at 'the desired amplitude. A

Other and further objects of our invenltion will be understood from the specification hereinafter following by reference to the accompanying drawings, in which:

Figure 1 is a front view of the cone speaker of our invention; Fig. 2 is a lateral cross-sectional view taken through the cone s ker casi of Fig. .1 and showing the e ectrom netic driver and a portion of the cone diap ragm in side elevation; Fig. 3 is a fragmentary cross-sectionalview showing the method we employ for locking together the edges of the cone speaker casing; and Fig. 4 is 'a detailed fragmentary view showing one of. the pressed side joints by which the sides of the cone speaker casing are bound together.

riphery by an annular supporting member with a relatively large sized rim between the supportingmember and the conical portion of the diaphra Heretofore in the art variousfbrms of zechanicalmovements have been interposed between the driver and the cone diaphragm proper. It has also been considered heretofore that in order to secure a desired degree of amplitude in sound reproduction it was necessary to employ a cone diaphragm having adiameter of more than nine inches. By our invention we radically depart from the characteristics of the prior" art and provide a relatively small sized cone diaphragm as a sound reproduce'r for radio broadcast entertainment and It has we flexibly .suspend the .cone diaphragm at of the diaphragm for reinforcing such waves and increasing the amplitude of the reproduced sound. \Ve prefer to construct the casing for the cone speaker from sheet metal which is pressed into a hollow triangular prism for housing all of the sound reproducer parts. Abutting edges of the casing are provided with locked-together joints for insuring a tight: seal at the edges of the casing. 2

Referring now to the drawings in more detail, the sheet metal casing which encloses the parts of the cone speaker is represented as having contiguous quadrangular walls l and 2 bent with respect to each other. The

side portion 1 is provided with a grille 3 through which sound waves may emanate,

The sides of the casing are formed by triangular sheet members 4 and 5. The lower edges of the front and rear walls 1 and 2 terminate in curved portions 6 and 7 which 00- operate with the similarly curved portions 8 and 9 of a base plate 10, forming a rigid lock joint therebetween; The front and rear walls 1 and 2 are also provided with turned over edges 11 and 12 to form rigid connections with the side me'mbeis 4 and 5. The electromagnetic driver is mounted within the casing upon an angularly disposed bracketmember 14. The. electromagnetic driver is enclosed by a case 15 and is provided with a permanent magnet system 16. The mounting of the driver within the easing is such that the reciprocating member 17 which leads from the armature within the case 15, is disposed in a line substantially normal to the front plate lof the casing. Behind the front wall 1 but substantially spaced therefrom we provide a supporting member 18 carried by means of a bracket 19 secured to the'base plate 10. The supporting member 18 is centrally apertured, as represented at 20, and extending inwardly from the edges of the aperture is a resilient annular gasket 21' to which the-outer periphery of cone diaphragm 22 is secured. 'The apex of the cone diaphragm 22 is secured by means of a reinforcing member 23, to-. the plunger 17 wherebywsound vibrations are imparted to the sound reproducing diaphragm 22 from the electromagnetic driver within case 15. It will be observed that the supporting member- 18 for the cone diaphragm 22 is spaced, as represented at 24, from the rear of the front wall l', thereby avoiding undesirable compression forces. within the casing. 3

As illustrated the rear wall 2 and the base plate 10 of the casingfare disposed at such an angle that the divergence of these plate members forms a pocket behind the rear of the conical diaphragm 22 tending to refleet sound waves from the rear of the diaphragm in the direction of the sound waves emanating from the front of the diaphragm, thereby reinforcing such sound waves and increasing the amplitude of the reproduced sound. The direction of prop agation of the reproduced sound is upwardly and outwardly, consequently the sound is distributed over a relatively large area when the cone speaker is mounted upon a horizontal support. The wall 2 and the base plate 10 diverge in the same direction that the side walls of the diaphragm 22 diverge. thus insuring a uniform distribution of the sound. It will he manifest that the entire casing for the cone speaker may be pressed from sheet metal and the edges thereof iocked together in pressing operations. the triangular prism of the casing provides angles of sixty degrees between the front, rear, and bottom walls. giving symmetry of construction and simplifying the pressing operations employed in the manufacture of the cone speaker.

\Vhile we have described onc constructional form'of our invention we desire that it be understood that modifications may be made and that no limitations upon the invention are intended other than are imposed by the scope of the appended claims.

What we claim as new and desire to secure by Letters Patentof the United Stalcs is a follows:

1. An electromagnetic sound reprod/nccr comprising in combination a- 'prisrn'shaped casing, an electromagnetic driver positioned within said casing, and a cone diaphragm having its base disposed adjacent one wall of said casing and its apex connected with said electromagnetic driver within said casing whereby sound waves reproduced by said cone dia hragm arc directed upwardly and outwarcly when said triangularly shaped casing is mounted upon a horizontal base.

2. An electromagnetic sound rcproduccr comprising in combination a casing having' an aperture-d front. and a rear wall diverging with respect to each other, an clcctromag-.

nctic driver positioned within said casing in a plane substantially between said walls.

a cone diaphragm having its base located in a plane substantially parallelwith the front wall and its apex connected with said electromagnetic driver, whereby sound reproduced by said cone diaphragm is directed upwardly and outwardly when said casing is dis osed on a horizontal .base.

3. n electromagnetic sound reproduccr comprising in combination a casing in a shape of a hollow triangular prism, an elec tromagnetic driver mounted within said easing, a cone diaphragm having its basedisposed in a plane substantially parallel with one wall of said casing and having its apexconnected with said electromagnetic driver at a central point within said casing whereby sound reproduced by said cone diaphragm is directed upwardly and outwardlywhen said casing is mounted upon a horizontal base.

4. An electromagnetic sound reproduccr comprising in combination a casing having three quadrangular closure members disposed at substantially equal angles with respect to each other. an electromagnetic driver mounted sub tantially at the center of one of said closure members, a cone diaphragm having its base disposed in a plane substantially parallel-.140 another of said closure members, and means securcd to said first mentioned closure member for supporting said cone diaphragm, and a connection betiveen the apex of said cone diaphragm and said electromagnetic driver whereby mechanical vibrations are imparted to said cone diaphragm.

5. In an electromagnetic sound reproducer tho-'combination of a casing in the shape of a hollow triangular prism, an electromag netic driver positiohed centrally within said casing, a plunger member connected with said electromagnetic driver,- and lying in the plane that bisects one of the angles of said casing, a .cone diaphragm, means for mounting said cone diaphragm adjacent the side of said casing opposite the aforesaid angle, and a connection between the apex of said cone diaphragm and said, plunger member whereby sound reproduced by said diaphragm is propagatedupwardly and outwardly when said casing is mounted upon a horizontal base.

6. An electromagnetic sound reproducer comprising .in combination a casing in the shape of a hollow triangular rism, an electromagnetic driver centrally disposed within said casing, a cone diaphragm having its apex connected with said electromagnetic driver and having its base extending in a plane substantially parallel with oneesideof said casing, the reinainin sides of said casing forming a pocket in tie rear of said diaphra m .for reflecting sound waves emanating mm the rear of said diaphragm in the direction of sound'waves emanating from the front of said diaphragm for the reinforcement thereof.

- 7. In an electromagnetic sound reproducer support for a cone diaphragm mounted upon the other of said bracket members, a cone diaphragm resiliently suspended in said support and having its base lying in a plane substantially arallel with one of said first mentioned wa l" ortions, and a connectionbetween said e ectroma netic driver and the apex of said cone diap ra whereby sound reproduced b said diap ragm is directed upwardly and outwardly when said casing is mounted upon a horizontal base.

In testimony whereof we afiix our signatures.

FREDERICK DIETR'ICH. WILLIAM H. GERNS.

ges thereof with a pair of end Wall'- 

